When the coronavirus hit the world in 2020, the Alvin Ailey American Dance Theater, keeping with its founder’s mission of bringing dance to the people, offered a “Revelations” Workshop online. The 13-minute video taught viewers phrases from each of the dance’s three sections. Choreographed in 1960 to gospel, spirituals, and blues, Revelations was an instant classic. I’ve been seeing this dance every few years since the early 70s and it never gets old, never looks dated, and never loses its power to uplift. By the time the dancers get to “Rocka My Soul,” viewers are practically jumping out of their seats. In its engagement at Sadlers Wells, the Ailey company has Revelations on three of its four programs. “Ailey Classics” is an archival showcase; “Modern Masters” includes Twyla Tharp’s Roy’s Joys; “Contemporary Voices” foregrounds recent work by Robert Battle and Kyle Abraham; and “21st Century Creations” features In a Sentimental Mood by the up-and-comer Jamar Roberts. —Laura Jacobs